Brain tumors are among the most deadly adult tumors and account for approximately 2% of all cancer deaths in the United States. The primary reason for the high mortality rate includes the inability to remove the complete tumor tissue due to the location of the tumor deep in the brain, as well as the lack of a satisfactory continuous imaging modality for intraoperative intracranial procedures.
Surgical resection of the tumor is considered the optimal treatment for many brain tumors. To minimize the trauma to the surrounding brain tissues during surgical resection, endoscopic port surgery (EPS) was developed, which is a minimally-invasive technique for brain tumor resection which minimizes tissue disruption during tumor removal.
However, due to the lack of satisfactory continuous imaging modality, it is extremely challenging to remove brain tumors precisely and completely without damaging the surrounding brain tissue using traditional surgical tools. As a result, patients may develop hemi paresis, cognitive impairment, stroke or other neurological deficits due to the procedure.
MRI (Magnetic Resonance Imaging) provides excellent soft-tissue contrast and the ability to distinguish the tumor margins, which enables a neurosurgeon to perform the procedure with less trauma to surrounding tissues during tumor resection. However, due to the strong magnetic field required for the MRI to operate commonly used sensors and actuators in conventional robotic systems are precluded from being used in MRI-compatible robots.
Several MRI-compatible surgical robotic systems have been designed in recent years. For example, Masamune, et al. (“Development of an MRI-compatible needle insertion manipulator for stereotactic neurosurgery”, J. of Image Guided Surg., 1995, 1(4), pp. 242-248) developed an MRI-compatible needle insertion manipulator dedicated to neurosurgical applications using ultrasonic motors; Wang, et al. (“MRI compatibility evaluation of a piezoelectric actuator system for a neural interventional robot”, In Proc. IEEE Eng. Med. Biol. Soc. Annu. Int. Conf., 2009, pp. 6072-6075) built an MRI-compatible neural interventional robot using a piezoelectric actuator system.
Kokes, et al. (“Towards a teleoperated needle driver robot with haptic feedback for RFA of breast tumors under continuous MRI”, Med. Image Anal., 2009, 13(3), pp. 445-455) developed an MRI-compatible needle driver system for Radio Frequency Ablation (RFA) of breast tumors using hydraulic actuation.
Yang, et al. (“Design and control of a 1-DOF MRI-compatible pneumatically actuated robot with long transmission lines”, IEEE/ASME Trans. Mechatron., 2011, 16, pp. 1040-1048) presented a design and control of an MRI-compatible 1-DOF needle-driver robot using pneumatic actuation with long transmission lines.
Fischer, et al. (“MRI-compatible pneumatic robot for transperineal prostate needle placement”, IEEE/ASME Trans. Mechatron., 2008, 13(3), pp. 295-305) developed an MRI-compatible robot for prostate needle placement using pneumatic actuation.
Krieger, et al. (“Design of a novel MRI compatible manipulator for image guided prostate interventions”, IEEE Trans. Biomed. Eng., 2005, 52(2), pp. 306-313, and “Development and preliminary evaluation of an actuated MRI-compatible robotic device for MRI-guided prostate intervention”, In Proc. IEEE Int. Conf. Robot. Autom., 2010, pp. 1066-1073) developed an MRI-guided manipulator for prostate interventions using shaft transmission and piezo-ceramic motors.
Although the above-mentioned robotic systems are MRI compatible, they unfortunately cannot be used to reach a target which is not in the “line-of-sight” due to limited Degrees Of Freedom (DOF) of the robots intended for use in their systems.
N. Pappafotis, et al. (“Towards design and fabrication of a miniature MRI-compatible robot for applications in neurosurgery”, in Int. Design Eng. Technical Conf. & Computers and Information in Eng. Conf., 2008) described a preliminary prototype of Minimally Invasive Neurosurgical Intracranial Robot (MINIR) using Shape Memory Alloy (SMA) wires as actuators.
An improved design of MINIR was proposed by Ho, M. and Desai, J. P. (“Towards a MRI-compatible meso-scale SMA-actuated robot using PWM control”, in Int. Conf. on Biomedical Robotics and Biomechatronics, 2010, pp. 361-366) which improved several limitations of previous prototypes. The improved MINIR had individual SMA actuators for each joint. All joints were located on the outside surface of the robot and all wiring and tubes were routed inside the robot, thus attaining a more compact and easier shielded robot.
M. Ho, et al. (“Towards a MR image-guided SMA-actuated neurosurgical robot,” in Proc, IEEE Int. Conf. Robot, Autoin., 2011, pp. 1153-1158; and “Toward a meso-scale SMA-actuated MRI-compatible neurosurgical robot,” IEEE Trans. Robot., 2012, Vol. 28, No. 1, pp. 213-222), presented an MRI-compatible minimally invasive neurosurgical intracranial robot (MINIR) using SMA wires as actuators.
In M. Ho, et al. (“Towards a MR image-guided SMA-actuated neurosurgical robot”, in proceedings of 2011 IEEE Int. Con. On Robotics and Automation, 2011, pp. 1153-1158), the force behavior of SMA (Shape Memory Alloy) actuators in the bent configurations was investigated.
Though the approach of using SMA (Shape Memory Alloy) wires as actuators was successful, there are significant limitations. Specifically, heating current has to be applied to the SMA wires while actuating the robot. The current can interfere with the magnetic field inside the MRI bore, and thus may lead to distortion in the image. Although the effects are limited and the profile of MINIR can be easily identified in the MR images, as presented in M. Ho, et al. (“Towards a MR image-guided SMA-actuated neurosurgical robot”, in proceedings of 2011 IEEE Int. Con. On Robotics and Automation, 2011, pp. 1153-1158), the noise and distortion still causes difficulties in finding precise tumor boundaries.
It is clear that an improved surgical system for tissue biopsy, RF-ablation and other neurosurgical procedures involving tumor resection is needed in which the MRI noise is eliminated by using a real-time tracking and navigation technique which provides precise continuous virtual 3-dimensional visualization of the dynamical changes of the target during the surgery, and which aids in early detection of intra-tumoral hemorrhaging which may occur during resection, as well as in keeping track of shifting margins of the tumor during the surgical process, thus reducing potential complications of the surgery.